A siloxane compound having —HSiRO— (wherein R represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenoxy group) is used as a precursor of a silicon oxide-based thin film. According to electric characteristic and optical characteristic, a silicon oxide-based thin film is applied as a low-dielectric-constant interlayer insulator for multilayer circuit structures for semiconductor devices or an optical component such as a microlens.
However, the above siloxane compound undergoes alteration due to polymerizing, which gives rise to a problem on use. For example, when applied to a wet coating technique including a sol gel process, a coating composition of the siloxane compound undergoes viscosity increase or gelation, failing to form a thin film stably. In application to thin film formation involving vaporization, it is difficult to vaporize a given amount of the precursor stably. Furthermore, a polymerization product can contaminate thin film formation equipment and a thin film formed and clog feed pipes.
To address the above problems, Patent document 1 discloses a combined use of a phenol compound, such as 2,6-di-t-butyl-4-methylphenol, with a siloxane compound, and Patent document 2 discloses a combined use of a phenol compound typified by 4-methoxyphenol with a siloxane compound. These conventionally proposed phenol compounds produce only insufficient stabilizing effects nevertheless.
Patent document 1: JP-A-2003-238578
Patent document 2: WO 2004/27110